The way that buildings have been built has not changed in many years. However there is a need to improve the performance of buildings driven by the need to reduce heating bills and, by association, the reduction of carbon dioxide in the atmosphere which effects global warming and climate change.
A building is constructed in a way that tries to maintain a comfort level where people can live and be sheltered from the elements. Ideal living conditions are neither to hot or too cold, irrespective of the climate which could be too hot, too cold or to wet.
In order to maintain this comfort level, the interior living conditions need to be either heated or cooled. It is desirable that the energy used is minimized, whilst still maintaining the comfort level. This can be achieved by insulating the building. It is desirable to make the building more air tight to reduce heat loss. It is also desirable to stop noise pollution from either the outside of the building or from the inside of the building.
When a building is thermally efficient and air tight, there is an increased risk that humidity can increase in the building which can cause condensation. Standard or interstitial condensation carries the risk of leading to detrimental degrading of the building fabric.
Conventional buildings are typically constructed using a cavity wall, comprising outer and inner leaves (typically but not necessarily masonry) and a cavity between them. The cavity is typically filled with an insulation material. This conventional way of constructing walls has the disadvantage of having thermal bridges where the inner and outer leaves are coupled together by ties; these thermal bridges between the cold exterior surface and the warm interior surface (or vice versa) provide a bridge along which heat, sound, fire and moisture can travel.
It is known to construct a building using modular panels which are pre-fabricated and assembled on site. The off-site manufacture of these modular panels is typically to a much higher tolerance (+/−1 or 2 mm (+/−0.04 or 0.08 in) than used in the construction process (+/−25 mm (0.98 in)). This disparity can lead to adjustment of the panels being required when installed on-site. This problem particularly arises with the positioning of windows and doors.
Services, such as electricity, water and heating/cooling are typically installed once the building shell has been constructed. To install these services, channels in the internal leaf of the walls are chased out and the necessary wiring, conduits or pipework fitted. This has the disadvantage that air bridges may be introduced, reducing the air-tightness of the building. This disadvantage is further increased in buildings using pre-fabricated panels; in this case part of the insulation may be chased out, reducing the insulation of the panel and also potentially introducing holes in the panel, resulting in air flow through the panel.